The actual role of bacteria in the low-temperature formation of
dolomite remains to be demonstrated. The specific mechanism of
dolomitization, involving sulfate-reducing bacteria, has not yet been
demonstrated.

I wonder if someone has any updates on this. The reference given in the Wikipedia article is from 2000, from a source titled suspiciously "Journal of Conference Abstracts". Now it's 2013 and maybe someone else has found out something new.